In apparatus such as rotary punchers, slitters, embossers, sealers and the like, which involve the use of a pair of cooperating rotary tools, the tools frequently have been mounted on outboard ends of driven cantilever shafts, to facilitate thread up of the work piece, maintenance of the equipment and the like. A problem with such apparatus has been that the ends of the cantilever shafts tend to deflect or flex slightly. Such deflection can lead to premature wear of the tools; and to incomplete or irregular punching, slitting, embossing or sealing. These problems in turn can require frequent shut down of the apparatus for adjustment, replacement of worn and broken parts and other repairs made necessary by such deflection of the cantilever shafts. One potential source of such deflection is radial and axial run-out of bearings supporting the shafts.
One solution attempted for such problems has been to provide, rigidly attached to the frame of the apparatus, an additional rotary support for the free end of each cantilever shaft. Aside from the difficulty of threading up and maintaining such an apparatus, the additional support may over constrain the shaft; so that, errors in alignment can cause high stresses on shafts, bearings and tools, leading ultimately to failures. Another solution is described in U.S. Pat. No. 186,109 which shows half journal bearings mounted inboard of the tools from the ends of the cantilever shafts. This arrangement over constrains the shafts and would be expected to lead to early failure of the half journals. U.S. Pat. No. 4,485,710 shows a paper cutting machine in which movement of noncantilever shafts in low precision bearings is minimized by a bearing unit supported between a pair of non-cantilever shafts. U.S. Pat. No. 4,770,078 shows a cutting and scoring apparatus in which tools mounted on cantilever shafts are prevented from moving by rollers mounted in the frame of the apparatus. This arrangement also results in over constraint of the shafts and tools.
Thus, a need has existed for a solution to the problem of controlling movement of tools mounted on cantilever shafts, without over constraining the shafts, tools or supporting bearings. A need has also existed from a solution to the problem of controlling run-out of the supporting bearings, which can contribute to movement of the tools.